To prevent repetitive strain injuries and general discomfort associated with the use of computer keyboards and the like, attempts have been made to create ergonomic keyboards and associated hardware. There are many unusually shaped keyboards and cursor positioning devices such as the mouse. However, there is no device which adequately addresses the issue of Repetitive Strain Injury with a convenient and simple solution.
Carpal Tunnel Syndrome(CTS), a form of tendinitis within the arms and wrists of a user of keyboards, is caused when a person's job requires the person to use manually actuated devices for extended periods of time. Ligament friction and joint stress can cause temporary or permanent pain.
U.S. Pat. No. 5,426,449 reveals a keyboard which rotates the hands and supports them on their sides. This may help the underside of the wrist, but the same problems would develop on the side. Also, in this configuration, the entire weight of the arms would rest upon the side of the hands which would soon cause discomfort.
U.S. Pat. Nos. 5,416,498 and 5,339,097 issued to Grant show a keyboard having a "split-key" arrangement with the key face angled toward the user and having cursor control located for the thumb. When using Grant's keyboard the user's wrists and arms have no support, and to use the mouse with the user's thumb's, the user's wrists would incur a severe angle. This severe angle between the top of the forearm and the top of the hand would increase wrist stress even more.
U.S. Pat. No. 5,145,270 issued to Darden reveals a Reverse Slope Keyboard which has a raised rear portion and a wrist support at the top so that the user may strike the keys on a reversely sloping keyboard surface. Darden's keyboard represents the greatest improvement until now and yet does not solve the problem of user stress. Darden's keyboard does make the leap to a reverse slope, however the support is defined support as a wrist support. From the figures included in Darden's patent, one can see that the wrists are supported at the forearm hand junction, increasing pressure upon the Carpal Tunnel and thus inducing previously mentioned Carpal Tunnel Syndrome. Darden's keys are arranged in a stepwise fashion upon the reverse sloping face of the keyboard. The keys are large and must be struck vertically(to make clearance for fingernails). The important problem here is that if the user's hand is supported at the wrist, and the user's fingers must move in a perpendicular plane to that generated by the user's forearms, the user's fingers become very tired very quickly. Thus, when using Darden's keyboard, pain and discomfort would come rapidly and the problem that this art form attempts to address would remain.
U.S. Pat. Nos. 5,120,938 and 5,029,260 by Rollason reveal a keyboard designed to be used in the lap of the user. Rollason's keyboard, while convenient, does not address the issue of repetitive strain injury correctly. Rollason does not address the issue of wrist stress because the keys are facing the user which causes one's wrists to be bent backwards. And, while in the lap of the user, there is no support for the user's forearms unless the user's forearms rest on the user's chair arm rests. The user would encounter the difficulty of having a mis-match between the height of the arm-rest and the height of the user's elbows. Finally, this keyboard would be cumbersome and extremely uncomfortable if used on a table top. Also, while using Rollason's keyboard in one's lap, one would eventually drop one's wrists down and thus incur the strain associated with a severe angle between the hand and forearm.
None of these patents correctly understands and addresses the joint stress issue. To fully address the hand stress issue, one must do the following: Place one's hands in one's lap, palms facing up, and find the position which is the most comfortable. The position you probably have found is one where there is a slight angle between the top of your forearm and the top of your hand(slightly greater than 180 degrees). Also, one's hands are probably in the prehensile or grasping position, as though you would not have to move your fingers and thumb far to grab something. Now, while maintaining the same hand and forearm positions, roll the forearms over until the palms are facing down. This is the ideal position for the hands to operate in. And, none of the disclosed patents makes an attempt to put the hand and forearm into this position.
The following is a list of disadvantages within the current art of ergonomic interfaces:
1) Excessive pressure is placed upon the wrist and thumb joints. This pressure is applied by direct force from another object upon which the wrist is resting. Abnormal pressure is also created within the wrist and thumb joints when the angle between the top of the forearm and the top of the hand becomes less than 180 degrees. PA1 2) Current attempts to address the joint stress problem support the wrists of the user, thereby aggravating the problem. PA1 3) Existing patents have small radii on most edges which can jab into the user's hands and become uncomfortable after extended use. PA1 4) Existing patents force the user to sit at the desk and work, causing back problems, and existing patents that utilize the lap-mounted position are cumbersome and cause an angle between the top of the forearm and the top of the hand which is less than 180 degrees. PA1 5) Existing patents and hardware force the user to strike or push the keys of the keyboard. The striking motion or pushing motion of the keys is inherently unnatural for hands adapted to grasp, grip, or pull towards the palms of the hands. PA1 6) Existing patents and hardware have large keys and are spaced far enough apart to require large finger movements to strike them. PA1 7) Existing key arrangements do not lie in the path that the natural motion of the fingertips take as the fingers move away from the palm of the hand. PA1 8) Existing keys, once struck, "bottom out" and stop abruptly sending shock waves reverberating through the joints of the finger striking the key. PA1 9) Existing patents have keyboards made of hard plastic material which, over time, become uncomfortable. PA1 10) Existing patents do not provide forearm support in a convenient manner(i.e. incorporated as part of the keyboard or ergonomic interface). PA1 11) Existing patents require motion of the fingertips/hands that is inherently unnatural(i.e. pushing or striking motion as opposed to pulling motion). PA1 12) Existing patents do not require the hands to be in a truly prehensile or grasping position. PA1 13) Existing patent with reverse slope of keyboard face has keys arranged in a manner which requires awkward motion of the fingers(i.e. perpendicular to forearms). PA1 14) Existing patent with reverse slope of keyboard face does not have keys arranged normal to reversely sloping plane. PA1 15) Existing patents have keys arranged such that they are easily visible while in use. This discourages the keyboard user from memorizing the key positions and thus slows down the user's long term data entry speed. PA1 16) Existing patents do not provide palm support in a convenient manner such that keys can easily be reached even while the palms of the hands are supported. Existing patents may support the palm, but to actuate keys etc., the angle between the top of the forearm and the top of the hand is forced to bend at an angle of less than 180 degrees. PA1 17) Existing patents do not provide a convenient method of utilizing one's cursor position control in one's lap without creating an angle between the top of the forearm and the top of the hand which is less than 180 degrees. PA1 18) Existing patents do not have integral thumb recesses. PA1 19) Existing patents do not have grab handles for convenient movement of device. PA1 20) Existing patents do not have convenient power cord storage space. PA1 21) Existing patents do not provide a recessed area for the user's stomach(i.e. no belly space). PA1 22) Existing lap mounted patents are not contoured for groin and scrotal area. PA1 23) Existing patents do not incorporate a cursor control centrally located on reverse side of keyboard or centrally located on reverse side of cursor control pad. PA1 24) Existing patents do not provide dual space bars centrally located in recessed thumb area. PA1 25) Existing patents do not allow the fingers and thumbs to comfortably wrap around the keyboard surface in a grasping position. PA1 26) Existing cursor control pads do not incorporate a convex declined shape on cursor control surface. PA1 1) To provide manually actuated ergonomic interfaces(E.I.'s) for humans which create minimal pressure upon the wrist and thumb joints by supporting either the palm of the hands, the forearms, or both. Further reduction of wrist and thumb joint pressure to be accomplished by creating an angle of greater than or equal to 180 degrees between the top of the forearms and the top of the hands of the user while using the E.I.'s. PA1 2) To provide E.I.'s which do not support the wrists of the user directly thus inherently reducing stress(force per unit area) within the wrists. PA1 3) To provide E.I.'s with all surfaces that may come in contact with the user having large radii that will not jab into the user and thus be more comfortable for extended periods of use. PA1 4) To provide E.I.'s that can be used in a lap mounted position that does not force the user to sit immediately adjacent to his or her desk, which is not cumbersome and creates an angle of greater than or equal to 180 degrees between the top of the hands and the top of the forearms of the user, thus reducing back problems and/neck strain and other repetitive strain injuries(RSI). PA1 5) To provide E.I.'s which do not force the user to strike or push the keys of the keyboard. Rather than push or strike the keys, an E.I. is provided that has keys that are pulled with the hands in a more natural grasping motion, thus adapting the E.I. to the naturally evolved prehensile position of the hands of the user. PA1 6) To provide E.I.'s which have small keys that are spaced close enough together so as to require only minimal finger motion and force to actuate them. PA1 7) To provide a key arrangement which places the keys in the path that natural finger motion follows as the fingers move toward or away from the palm of the hands. PA1 8) To provide keys that will not "bottom out" abruptly, but will have sufficient cushioning once actuated such that minimal force is placed upon the finger joints at the completion of actuation; this will reduce forces within the finger joints and reduce wear and tear upon the fingers and their joints. PA1 9) To provide E.I.'s which have surfaces that are made from "soft" surfaces that provide cushioning to all parts of the user which may come into contact with the E.I., thus increasing the comfort level of the user over extended periods of use. PA1 10) To provide E.I.'s which have integral forearm supports thus increasing the convenience and acceptance of their use. PA1 11) To provide E.I.'s requiring natural motion of the fingertips and hands(i.e. pulling toward the palm/forearm as opposed to pushing or striking). PA1 12) To provide E.I.'s which force the hand into a true prehensile or grasping position. PA1 13) To provide a convex declined keyboard surface which allows the hands and forearms to be comfortably supported while minimal hand and wrist movement is required for key actuation. PA1 14) To provide a convex declined keyboard surface which has the keys arranged normally(perpendicular) to the keyboard face thus allowing the fingers to "pull" the keys while in the prehensile or grasping position. PA1 15) To provide E.I.'s which encourage the user to memorize the key locations and their associated characters or functions by locating the keys in such a way that it is difficult to view them. This encouragement to memorize, if acted upon, will increase the productivity of the user by increasing his or her data entry speed. PA1 16) To provide palm support in a convenient manner such that keys can easily be reached even while the palm is supported, while also maintaining an angle of greater than or equal to 180 degrees between the top of hand and the top of the forearm of the user. PA1 17) To provide E.I.'s with a convenient method of utilizing one's cursor position control in one's lap, while creating an angle greater than or equal to 180 degrees between the top of the hand, and the top of the forearm of the user. PA1 18) To provide E.I.'s with integral thumb recesses. PA1 19) To provide E.I.'s with grab handles for convenient movement of E.I. PA1 20) To provide E.I.'s with convenient power cord storage space. PA1 21) To provide E.I.'s with a recessed area for the user's stomach( i.e. belly space). PA1 22) To provide lap mounted E.I.'s contoured for groin and scrotal area. PA1 23) To provide E.I.'s with cursor position control centrally located on forward side of convex declined surface, or centrally located on reverse side of cursor control pad. PA1 24) To provide E.I.'s with dual space bars centrally located in recessed thumb area, such that they may be actuated by the natural grasping motion of the thumbs. PA1 25) To provide E.I.'s which allow the fingers and thumbs to comfortably wrap around the keyboard surface in a grasping position. PA1 26) To provide cursor control pads which incorporate a convex declined shape for the cursor control surface.